Cross-site scripting (XSS) vulnerability in Action View in Ruby on Rails 3.x before 3.2.22.3, 4.x before 4.2.7.1, and 5.x before 5.0.0.1 might allow remote attackers to inject arbitrary web script or HTML via text declared as "HTML safe" and used as attribute values in tag handlers.

The http_basic_authenticate_with method in actionpack/lib/action_controller/metal/http_authentication.rb in the Basic Authentication implementation in Action Controller in Ruby on Rails before 3.2.22.1, 4.0.x and 4.1.x before 4.1.14.1, 4.2.x before 4.2.5.1, and 5.x before 5.0.0.beta1.1 does not use a constant-time algorithm for verifying credentials, which makes it easier for remote attackers to bypass authentication by measuring timing differences.

Directory traversal vulnerability in Action View in Ruby on Rails before 3.2.22.1, 4.0.x and 4.1.x before 4.1.14.1, 4.2.x before 4.2.5.1, and 5.x before 5.0.0.beta1.1 allows remote attackers to read arbitrary files by leveraging an application's unrestricted use of the render method and providing a .. (dot dot) in a pathname.

actionpack/lib/action_dispatch/routing/route_set.rb in Action Pack in Ruby on Rails 4.x before 4.2.5.1 and 5.x before 5.0.0.beta1.1 allows remote attackers to cause a denial of service (superfluous caching and memory consumption) by leveraging an application's use of a wildcard controller route.

activerecord/lib/active_record/nested_attributes.rb in Active Record in Ruby on Rails 3.1.x and 3.2.x before 3.2.22.1, 4.0.x and 4.1.x before 4.1.14.1, 4.2.x before 4.2.5.1, and 5.x before 5.0.0.beta1.1 does not properly implement a certain destroy option, which allows remote attackers to bypass intended change restrictions by leveraging use of the nested attributes feature.

actionpack/lib/action_dispatch/http/mime_type.rb in Action Pack in Ruby on Rails before 3.2.22.1, 4.0.x and 4.1.x before 4.1.14.1, 4.2.x before 4.2.5.1, and 5.x before 5.0.0.beta1.1 does not properly restrict use of the MIME type cache, which allows remote attackers to cause a denial of service (memory consumption) via a crafted HTTP Accept header.

Active Model in Ruby on Rails 4.1.x before 4.1.14.1, 4.2.x before 4.2.5.1, and 5.x before 5.0.0.beta1.1 supports the use of instance-level writers for class accessors, which allows remote attackers to bypass intended validation steps via crafted parameters.